If you're flying with drives full of data, better encrypt the data first. I'd just use the drives as a backup target for borg backup. Then at the other end, restore everything. You might need a spare, empty drive to get that process going. Alternatively, use your favorite encrypted file system if you want to keep the data encrypted after arrival, maybe a good idea too.

Better plan some logistics for one or more drives failing during this process too. I assume you have an intact copy of the data at home. So you can get a new drive written and shipped to you if something goes wrong.

Why do you have to do all this in person anyway though? Can't you ship drives and have someone at the other end install them in a box for you? For that matter, is 80TB really too much data to transfer by network? With a mere 1 gbit connection it's about a week of transfer.